問71
頻出度★★★
Aさんは電子メールの宛先を次のように設定して送信した。この電子メールを受信したYさんは，電子メールに記載されていた送り先全員と送信者に返信の電子メールを送信した。Aさん，Xさん，Zさんの3人のうち，Yさんの送信した電子メールが届く人を全て挙げたものはどれか。 〔Aさんの電子メールの宛先設定〕 To: X Cc: Y Bcc: Z
平成29年度 春期 ITパスポート試験 問71
テクノロジ系ネットワーク › ネットワーク応用
This question's explanation and your answers so far.
解説
問 71
Incorrectア
A alone is not enough. A is the sender, so the reply reaches A, but X in the To field is visible to Y and is also included among the reply recipients, so X receives it too. This option overlooks X.
- イ
正解 The key point is that a recipient specified with Bcc (blind carbon copy) is completely invisible to the other recipients. A's settings are To: X, Cc: Y, Bcc: Z, so Y, who received this email, can only see the sender A, X in the To field, and Y (self) in the Cc field, and cannot know that Z exists in the Bcc field. When Y replies to “all the listed recipients and the sender,” the recipients become X in the To field, Y (self) in the Cc field, and the sender A. Excluding Y's own address, the only people who actually receive it are A and X. Since Z is hidden by Bcc, Y cannot include Z as a recipient, so Z does not receive it. Therefore choice イ, which lists the two people A and X, is correct.
Incorrectウ
It is wrong to include Z in addition to A and X. Z is specified with Bcc (a recipient in the Bcc field is not shown to the other recipients), so the recipient Y cannot see that Z exists and Z is not included among Y's reply recipients. Therefore Z does not receive it.
Incorrectエ
This makes a double error: it drops the sender A and includes the invisible Z. Y replies to the sender A, so A receives it, whereas Z in Bcc does not. The correct pair is A and X.
ここがポイント
- Recipients in the To and Cc fields are shown to all recipients, but recipients in the Bcc field are hidden from the other recipients and known only to the sender.
- When a recipient does a “reply to all,” they can only reply to the addresses visible to them (To, Cc, and the sender); a Bcc recipient cannot be included as a recipient.
用語